program SuperC ;

{$APPTYPE CONSOLE}

uses
  SysUtils;

var
n,k,i,j,c,b,a,s:integer;

begin
writeln('enter n');
readln(n);
writeln('enter k');
readln(k);
  a:=1;
  b:=1;
  c:=1;
for i:=1 to n do
  begin
    a:=a*i;
  end;
for j:=1 to (n-k) do
  begin
    b:=b*j;
  end;

for s:=1 to k do
  begin
    c:=c*s;
  end;
writeln(a div (b*c));
readln;
end.

 